Tag Archives: design

Spanish Solar Steep Slope inSanity!

Spanish utility-scale solar developers apparently have little concern for the slopes upon which they build photovoltaic plants, resulting in absolutely insane, erosion-causing, likely self-endangering developments such as this one.

A utility-scale solar facility in Spain built on an incredible severe grade.

A utility-scale solar facility in Spain built on an incredibly severe grade.

American utility-scale solar developments have a variety of laws governing their permitting, chief amongst them our beloved National Environmental Policy Act of 1970 (NEPA), which requires rigorous environmental impact assessment on all proposals involving the federal government in any way.  California, too has the California Environmental Quality Act (CEQA), passed just a few months after NEPA, which gives a similar level of scrutiny to state-only projects, as well as enhancing the level of NEPA’s review in many cases.  

One of the chief areas of impacts examined under NEPA/CEQA is impacts to soil resources and hydrology.  Because building a facility like the one above will inevitably cause terrible erosion, by denuding the slopes of the vegetation which hold down their soil, utility-scale solar developers in California have been forced to limit the areas they can build to relatively flat places.  For example, the Solar PEIS, BLM’s programmatic evaluation of solar on Public Lands in the southwest, excluded all areas with slopes greater than 5% from consideration for development.  

In practice, developers need even flatter areas.  Ivanpah SEGS, which was able to built on a “steeper” slope of 1.7%, because it didn’t require wholesale grading of the site, is probably amongst the steeper that will ever be built in the U.S. [Link to EIS from BLM].  BLM’s own regs state that photovoltaics, like the Spanish sites pictured here, need to be sited at a 3% grade or less.

Water diversion scheme for Genesis Solar Power Project, as depicted in the EIS.

Water diversion scheme for Genesis Solar Power Project, as depicted in the EIS.

The alternative is to dramatically alter the native hydrology, as occurred with the Genesis Solar Power Project, a 250MW parabolic trough project sited near Desert Center, CA.  [Link to the EIS from BLMinfo from CECinfo from NREL.]  In order to properly set up the troughs, they needed to grade the entire 1,950 acre site to a 1% or less grade, requiring the movement of over a million cubic yards of fill (picture a 1500 mile long convoy of standard sized dump trucks).  But this of course, dramatically altered the local hydrology: to prevent a catastrophic flood, they had to build massive water diversion ditches, a schematic of which can be seen here.  And still, during construction Genesis experienced what can only be described as a catastrophic flood.

Spain’s environmental review process, on the other hand, is much more rudimentary.  One of the things I’m focusing on this summer is getting my hands on Spanish EIS’s for utility-scale solar plants here, to compare the way they assess impacts, and how that may inform whether or not a plant gets built.  Clearly, impacts to hydrology were not thoroughly considered with these facilities.  All the pictures come from a paper by Prof. Matías Mérida at the University of Málaga, in which he develops a typology of impacts from photovoltaic plants.  I’ll write more about his typology in a future post.  You can see the original Spanish version here [PDF, with pictures] or a crudely Google Translate-translated English version here [PDF, no pictures].  (Even so, Google Translate still seems like magic to me.)  Unfortunately, I do not have a good source yet for which specific solar facilities these shots come from in Spain- I’m currently in correspondence with Prof. Mérida about it and will update this post when I find out.  Still, just gaze in wonder, and be grateful that this is one particular problem that utility-scale solar watchers in the U.S. don’t have to contend with.